Typically, consumer packaging, for household products, such as laundry detergent or the like, takes on the form of cardboard cartons, flexible bags and/or molded containers (e.g. tubs, buckets or the like).
Traditional molded containers are formed by an injection molding process from a polymeric/plastic material, such as polypropylene, polyethylene or the like. However, due to the amount of plastic material required, such molded containers tend to be heavier in weight and/or costlier to produce than other packaging options.
Recently, flexible containers have been introduced that include both a molded portion and a flexible portion. The flexible portion, typically a laminate film or the like, replaces an area of the container that would otherwise be formed of the molded plastic material. The flexible film portion is applied during the injection molding process and results in a container having significantly reduced weight. Additionally, the flexible portion is typically configured to include a printed label that includes graphics, such as product logo, product information and the like, thus, eliminating the need to apply a separate label to the container after the injection molding process; thereby reducing handling and secondary operations.
However, when such flexible film portions are applied during the injection molding process, problems have been apparent. The molded (i.e., crystalline plastic) portion tends to shrink in size as it cools during the injection molding process, while the laminate films used for the flexible portion do not experience the same shrinking phenomena. As a result, in many desired configurations of the flexible container, the flexible portion will appear loose or oversized as a result of being applied during the injection molding process.
Moreover, problems result from the configuration of injection molds required to form a molded portion having an aperture over which the flexible film portion is applied. In this regard, the portion of the mold that forms the aperture in the molded portion results in difficulty with being able to remove the flexible container from the mold (i.e., the flexible portion tends to stick to the core of the male die).
Therefore, a need exists to improve upon the method for making flexible containers. The desired method should result in a flexible container in which the flexible portion is form-fitted to the molded portion (i.e., the flexible portion does not appear oversized or loosely fit about the molded portion). In addition, the desired method should provide for the flexible containers to be readily removed from the injection molds, so as to eliminate problems associated with the flexible container sticking to the mold core post-injection mold.